Modern telecommunications networks use a layered network architecture that separates the physical elements or hardware (also called “resources”) and the software that perform a particular network operation. The network operation of call processing, i.e., the connecting of subscribers, comprises basic call software (which governs the functions to connect subscribers together) and call feature software (which governs the operation of feature services). Examples of feature services include call waiting (CW), call forwarding (CF), attendant emergency override (AEO), do not disturb (DND), three-way calling (TWC), etc.
Since the introduction of computer-based switching systems, the number of feature services provided to subscribers has grown dramatically. This has driven network software design to promote feature-related considerations of the call processing operation. Such considerations include fast developmental responses to new switch-based feature requests by subscribers, more varied and specialized features for subscribers, and development of feature software in various network company locations. Modern call software models, for example, of the networks of the recently introduced Intelligent Network (“IN”) type, handle these feature-related considerations by separating basic call software and call feature software. This separation provides basic call stability while allowing fast feature introductions.
However, the growth of subscriber feature services has caused an even larger growth in the number of interactions between the basic call software and the call feature software (known as “feature interactions”) to implement features during a call. In existing switching systems, these feature interactions are usually implemented by embedding special feature interaction checks throughout the basic call software. This permits interactions to be resolved despite a constantly growing feature set since all features are located in the same switching system. But, as a consequence of using such hard-coded software (which is customer-specific) with the basic call software, the entire switching system software rather than specific software is required to be upgraded with each new feature that is introduced. Moreover, feature interactions cannot be resolved in this manner in an IN-type network. In such a network, a feature may physically reside in a geographically remote location from the subscriber and the switching system and, thus, each newly introduced IN feature requires new switch software.
The growth of subscriber features has caused a similar problem in the network operation of administration that comprises administration software (which defines system and subscriber line characteristics) and call feature software (which defines the characteristics of call features). In particular, there is now a large number of interactions between the administration software and the call feature software to assign or modify features for respective subscriber lines. As with the call processing operation, these feature interactions are currently implemented by the use of hard-coded software with the administration software and, consequently, have limitations similar to those described above.
Consequently, there is a need for a call processing system that is more flexible in resolving feature interactions, both for the call processing operation and the administration operation.